drawing_book.c

#include <stdio.h>
int main()
    {
    int n,p,j=0,a[100000];
    scanf("%d",&n);
    scanf("%d",&p);
    for (int i=0;i<=n;i++)
        if (i%2==0)
        {
        j++;
        a[i]=j;
        a[i+1]=j;
    }
    if (a[p]-1<j-a[p]) printf("%d",a[p]-1);
    else printf("%d",j-a[p]);
    return 0;
}